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Aggregation Commands


For details on a specific command, including syntax and examples, click on the link to the command’s reference page.

Name Description
aggregate Performs aggregation tasks such as $group using an aggregation pipeline.
count Counts the number of documents in a collection or a view.
distinct Displays the distinct values found for a specified key in a collection or a view.
mapReduce Performs map-reduce aggregation for large data sets.

For a detailed comparison of the different approaches, see Aggregation Commands Comparison.